1. Field of the Invention
This invention relates to the production of expanded (puff extruded) farinaceous food products which can be incorporated into composite, center-filled snack products or other products, corn puffs, crispbread crackers, or other types of extruded products. In particular, the invention relates to a method of producing a crisp, expanded, farinaceous food product which eliminates the necessity of using a drying oven or other drying devices to produce a final product having the desired characteristics.
2. Prior Art
U.S. Pat. No. 3,615,675 describes a method of producing a light, puffed or expanded food product which has a core filled with an edible paste-like or creamy material. The expanded outer shell is produced by developing a mass of farinaceous food material containing a liquid; the development taking place under superatmospheric pressures at temperatures above the boiling point of the liquid, and then extruding the mass of farinaceous material through an orifice. Upon emerging from the orifice, the material expands significantly due to the vaporization of a portion of the liquid in the material. The material is extruded through a die having a generally annular cross-section. A filling tube extends coaxially through the center of the annular extrudate so that a filling material such as cheese fillings, peanut butter or the like can be injected into the interior of the expanded, farinaceous material to create a composite food product.
The farinaceous material which is extruded in the process of U.S. Pat. No. 3,615,675 contains from about 10% to 25% water. Generally, this process requires that water, in addition to that naturally present as moisture in the farinaceous material, e.g., corn meal, be added to the farinaceous material either before it enters the extruder or within the extruder barrel in order to allow the material to develop sufficient plasticity and flowability to be extruded.
Upon emerging from the extruder die, the extrudate has sufficient dimensional stability to be self-supporting. But, the water content of the extrudate is too high to allow for the crisp, crunchy texture which is desirable in the final product. Consequently, the product must be dried by passing it through a drying apparatus such as an oven to drive off a sufficient amount of water necessary to obtain the desired texture. Drying is also an important consideration in imparting shelf stability to the product. In order for the product produced by the prior art process to have the desirable crisp, crunchy texture and to maintain its texture over a reasonable shelf life, the moisture must be reduced to a level on the order of 2% to 3% by weight of the product. The use of drying ovens to achieve the necessary reduction in moisture content contributes significantly to the cost of the product, inasmuch as the ovens consume a great deal of energy, and considering the capital cost of large industrial scale drying ovens. Moreover, since the product must pass through the drying oven as it moves linearly from the extruder, the drying ovens take up a significant amount of floor space, further adding to the cost of the process.
There is a need in the art for a process for producing an expanded, farinaceous food product which has a crisp texture and commercially acceptable shelf life without the necessity of using a drying oven or other drying apparatus to remove water from the product.
Advantageously, the expanded, farinaceous food product having a crisp texture should be capable of being incorporated into a composite food product in contact with a paste-like or creamy material without undergoing a loss of texture.